feat(routing): decision logger via brain MCP session_log

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/routing/log_test.go

@@ -0,0 +1,81 @@
+package routing_test
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/mathiasbq/supervisor/internal/routing"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestLoggerLogDecision(t *testing.T) {
+	var captured map[string]any
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, http.MethodPost, r.Method)
+		assert.Equal(t, "/mcp", r.URL.Path)
+		body, _ := io.ReadAll(r.Body)
+		require.NoError(t, json.Unmarshal(body, &captured))
+		_ = json.NewEncoder(w).Encode(map[string]any{"jsonrpc": "2.0", "id": 1, "result": map[string]any{"content": []map[string]any{{"type": "text", "text": "ok"}}}})
+	}))
+	defer srv.Close()
+
+	l := routing.NewLogger(srv.URL)
+	err := l.LogDecision(context.Background(), routing.LogEntry{
+		SessionID:   "sess-1",
+		Skill:       "code_review",
+		Decision:    "local",
+		Message:     "model=qwen35, pass_rate=0.94",
+		ProjectRoot: "/home/x/proj",
+		DurationMs:  1234,
+		Failed:      false,
+	})
+	require.NoError(t, err)
+
+	params := captured["params"].(map[string]any)
+	assert.Equal(t, "tools/call", captured["method"])
+	assert.Equal(t, "session_log", params["name"])
+
+	args := params["arguments"].(map[string]any)
+	assert.Equal(t, "_routing", args["skill"])
+	assert.Equal(t, "decide", args["phase"])
+	assert.Equal(t, "skip", args["final_status"])
+	assert.Contains(t, args["message"].(string), "code_review: local")
+	assert.Equal(t, "sess-1", args["session_id"])
+	assert.Equal(t, "/home/x/proj", args["project_root"])
+	assert.Equal(t, float64(1234), args["duration_ms"])
+}
+
+func TestLoggerLogFailure(t *testing.T) {
+	var captured map[string]any
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		body, _ := io.ReadAll(r.Body)
+		_ = json.Unmarshal(body, &captured)
+		_ = json.NewEncoder(w).Encode(map[string]any{"jsonrpc": "2.0", "id": 1, "result": map[string]any{}})
+	}))
+	defer srv.Close()
+
+	l := routing.NewLogger(srv.URL)
+	err := l.LogDecision(context.Background(), routing.LogEntry{
+		SessionID: "s", Skill: "debug", Decision: "local", Message: "litellm down", Failed: true,
+	})
+	require.NoError(t, err)
+
+	args := captured["params"].(map[string]any)["arguments"].(map[string]any)
+	assert.Equal(t, "fail", args["final_status"])
+}
+
+func TestLoggerSurfacesUpstreamError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		http.Error(w, "down", http.StatusBadGateway)
+	}))
+	defer srv.Close()
+
+	l := routing.NewLogger(srv.URL)
+	err := l.LogDecision(context.Background(), routing.LogEntry{Skill: "x", SessionID: "y", Decision: "local"})
+	require.Error(t, err)
+}